A so-called digital camera direct printing system is becoming popular, which directly connects a printer to a digital still camera (to be referred to as a DSC hereinafter) via an interface such as a USB and transmits a photo image stored in a storage medium (memory card) in the DSC to the printer to make it print the image.
In this printing system, generally, the DSC transmits the JPEG file of a print target image to the printer. The printer converts the JPEG file into a printable data format by, for example, decompression, color conversion, and resize and prints the image.
The quality of images obtained by a DSC is dramatically improving. A high-resolution DSC capable of capturing and storing image data with 8,000,000 pixels or more is also commercially available. There is proposed a system that processes an image captured by such a high-resolution DSC into print data and transmits the data to a printer to make it print the image (patent references 1 to 3).
Patent reference 1 proposes a digital camera direct printing system capable of printing an image based on image data from a DSC and a print format including the paper size in a printer by using a unique print protocol that is not so general.
In patent reference 2 aiming at reducing the process load on a printer, a DSC converts a JPEG file into a printable data format by, for example, decompression, color conversion, and resizes and transmits it to a printer, thereby reducing the image process load on the printer.
In patent reference 3, a DSC corrects variations in color reproduction characteristic between printers, converts image data into a general image file such as JPEG, and transmits it to a printer. This allows for obtaining a stable image independently of the print characteristics of a printer.
Patent reference 1: Japanese Patent Laid-Open No. 8-32911
Patent reference 2: Japanese Patent Laid-Open No. 10-290470
Patent reference 3: Japanese Patent Laid-Open No. 2003-134457